Thread by @DrTomFrieden

How big of a threat does the Delta variant pose? New developments show that the challenges we face in controlling Covid are immense. Millions of lives are at stake globally. 1/

It’s now clear that Delta spreads more readily than initial strains of Covid. It’s at least two times as infectious. bit.ly/3hLFTU0 2/

Delta may or may not be more deadly on a case-by-case basis, but because there are so many more cases, more people will get very sick, and more will die. 3/

Vaccines that have been studied work very well against Delta, especially to prevent severe illness and death. Vaccines can save your life from Delta, as they can from other strains of Covid. 4/

https://twitter.com/DrTomFrieden/status/1410246297072902150

The higher infectivity of Delta means the threshold for herd immunity will be higher. 70% may have been enough before, but likely isn’t high enough against Delta. That’s why we’re seeing case increases even in places like the UK and Israel, which have high vaccination rates. 5/

Delta is already causing an increase in cases in the United States—especially in places with less vaccination coverage. 6/

Arkansas (35% of population fully vaccinated), Missouri (40%), and Louisiana (36%) are the three states seeing the highest rates of Covid cases per capita. 7/

The increase in US cases will be followed within weeks by an increase in hospitalizations and deaths, almost entirely among people who have not been fully vaccinated. 8/

Unless action—vaccination, masking, distancing—is taken now, this increase in cases will continue into September and make return to school more complicated. Everyone should get vaccinated. 9/

Whether you should wear a mask depends on:

—Who you are (weak immune system?)
—What you’re doing (indoor aerobics in poorly ventilated gym?)
—Where you are (community with lots of Covid spread?)

Fully vaccinated people don't need to mask in many places, but it doesn’t hurt. 10/

Vaccination is the surest way to stop Covid, including the Delta variant. Low vaccination rates increase the disruption the virus will cause. 11/

Increasing vaccination rates will be most effective if tailored to each community, addressing both convenience and concerns, and avoiding communication or partisanship that can increase resistance. 12/

Vaccination verification can facilitate reopening sooner and more safely, but has unfortunately become politicized, making it harder to implement. 13/

Delta may well not be the worst variant the virus will deal us. 14/

We won’t know if the vaccines need to be tweaked or if boosters are needed unless there are breakthrough infections, which can tell us whether and which people may need boosters, and how often, if at all. 15/end